Antibacterial Activity of Rhodomyrtus tomentosa (Aiton) Hassk. Leaf Extract against Clinical Isolates of Streptococcus pyogenes

Table 1

The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of antibiotics, ethanol extract of Rhodomyrtus tomentosa, and rhodomyrtone against clinical Streptococcus pyogenes isolates.

Antibacterial agents	Antibacterial activity (μg mL^−1)						Resistance (%)
	*MIC50	^†MIC90	MIC range	^‡MBC50	^§MBC90	MBC range
Antibiotics (𝑛=47)
Erythromycin	<0.015	0.031	<0.015–0.125	0.031	0.031	<0.015–0.125	0
Penicillin G	<0.015	<0.015	<0.015–0.062	<0.015	0.031	<0.015–0.062	0
Plant extract/compound
Ethanol extract (𝑛=47)	7.81	15.62	3.91–62.50	15.62	15.62	3.91–62.50
Rhodomyrtone (𝑛=14)	0.78	1.56	0.39–1.56	1.56	1.56	0.39–1.56

*MIC at which 50% of the isolates were inhibited (MIC₅₀).
^†MIC at which 90% of the isolates were inhibited (MIC₉₀).
^‡MBC at which 50% of the isolates were killed (MBC₅₀).
^§MBC at which 90% of the isolates were killed (MBC₉₀).
𝑛: Number of test isolate.